1. Field of the Invention
The present invention relates to information reproduction apparatuses, and in particular, to an information reproduction apparatus for reproducing original information from a recording medium containing information divided into information units based on which errors can be detected.
2. Description of the Related Art
Information reproduction apparatuses for reproducing information recorded on a tape or disk recording medium include magnetic reproduction apparatuses that use a fixed magnetic head and magnetic tape to perform reproduction by dividing digital signals into blocks, and magnetic or optical reproduction apparatuses that use an optical pickup and optical disk or the like to perform reproduction by dividing digital signals into blocks.
In the magnetic reproduction apparatuses that use a fixed magnetic head and magnetic tape, when an error is detected from data in an information unit in a block used for reproduction, a portion of the magnetic tape on which the block is recorded is played while ignoring the block in which the error was detected and rewinding the magnetic tape, and this step is repeatedly performed until no errors are detected at all from information units in the block.
In the magnetic reproduction apparatuses, track width and the width of the information reading unit (hereinafter referred to as the "head tip") of the magnetic head, has become smaller with recent increases in storage capacity of recording media for information reproduction apparatuses, and the intervals between tracks has decreased. Thus, it is difficult for the head tip to travel on the same track used when recording was performed, particularly when the magnetic tape slightly fluctuates perpendicular to the travelling direction of the magnetic tape.
In particular, in the case of the so-called "multihead-tip, multitrack" magnetic recording apparatus that uses a plurality of reproduction head tips to perform simultaneous reproduction from information units on a plurality of recording tracks, in contrast to the case of a single-head-tip, single-track magnetic recording apparatus, it is almost impossible for the tracking control to simultaneously position all the reproduction head tips so as to maintain correspondence with all the tracks having recordings.
Consequently, errors frequently occur in the information units in a block used for reproduction, and the duration and time elapse (hereinafter referred to as "block restoration time") required to cancel information-unit errors in the block increases further. Accordingly, an information reproduction apparatus that rapidly and stably reproduces original information recorded on a recording medium is in great demand.
As described above, when the magnetic reproduction apparatuses using the fixed magnetic head and the magnetic tape detect an error from a block used for reproduction, they ignore the error-detected block and rewinding the magnetic tape, and this step is performed repeatedly until no errors are detected at all from information units in the block. However, this has a problem in that the block restoration time greatly increases because the repeated reproduction requires a very long time, depending on the conditions of the fixed magnetic head and the magnetic tape.
In addition, the number of times of the reproduction must be repeated varies depending on the conditions of the fixed magnetic head and the magnetic tape. As a result, time intervals of the restored block and restored blocks subsequent to the error-detected block are irregular. Therefore, a problem arises in that the repeated reproduction cannot cope with a case where original information must be restored by outputting reproduced information units at a predetermined cycle and in a predetermined order.